Various types of electrostatically aided coating equipment are known. There are, for example, the devices and systems illustrated and described in U.S. Pat. Nos. 6,423,143; 6,021,965; 5,944,045; RE35,883; 5,787,928; 5,759,277; 5,746,831; 5,737,174; 5,727,931; 5,725,150; 5,707,013; 5,655,896; 5,632,816; 5,549,755; 5,538,186; 5,526,986; 5,518,186; 5,341,990; 5,340,289; 5,326,031; 5,288,029; 5,271,569; 5,255,856; 5,221,194; 5,208,078; 5,197,676; 5,193,750; 5,154,357; 5,096,126; 5,094,389; 5,078,168; 5,033,942; 4,982,903; 4,932,589; 4,921,169; 4,884,752; 4,879,137; 4,878,622; 4,792,092; 4,771,729; 4,413,788; 4,383,644; 4,313,475; 4,275,834; 4,085,892; 4,020,866; 4,017,029; 3,937,400; 3,934,055; 3,933,285; 3,893,620; 3,291,889; 3,122,320; 3,098,890; 2,673,232; 2,547,440; and, 1,655,262; as well as WO 2005/014178; GB2,166,982; U.K. Patent Specifications 1,393,333 and 1,478,853; JP4-267961; JP4-200662; JP7-88407; JP51-54638; JP54-101843; JP4-66149; JP3-178354; JP3217394 and, JP3378058. U.S. Pat. No. 4,337,282 is also of interest. The disclosures of these references are hereby incorporated herein by reference. This listing is not intended to be a representation that a complete search of all relevant art has been made, or that no more pertinent art than that listed exists, or that the listed art is material to patentability. Nor should any such representation be inferred.
One characteristic typically associated with systems of the types illustrated and described in these disclosures is that the high magnitude potential applied to the dispensing device also appears across the voltage block. This potential results in electrical stress to voltage block components, which can ultimately lead to the failure of such components. Because of this, efforts have been directed toward reducing the magnitude of the potential applied to the atomizer, in order to reduce voltage stress on components of the voltage block. However, in the past, such efforts often have had a deleterious effect on the efficiency with which atomized coating material particles are transferred to the articles (hereinafter sometimes targets) which are to be coated by the atomized coating material particles. This is to be understood. In the prior art, reduced high magnitude potential means reduced transfer of electrons to the coating material particles as they are atomized.
This application describes an effort to reverse the reduced transfer efficiency which in the past has attended reducing the magnitude of the potential supplied to the atomizer.